Te optical switch with high extinction ratio based on slab photonic crystals

ABSTRACT

The present invention discloses a TEOS with a high extinction ratio based on slab PhCs which comprises an upper slab PhC and a lower slab PhC connected as a whole; the upper slab PhC is a first square-lattice slab PhC, the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating-square pillar, three first flat dielectric pillars and a background dielectric, the first flat dielectric pillars include a high-refractive-index dielectric pipe and a low-refractive-index dielectric, or 1 to 3 high-refractive-index flat films, or a low-refractive-index dielectric; the lower slab PhC is a second square-lattice slab PhC with a complete bandgap, the unit cell of the second square-lattice slab PhC includes a high-refractive-index rotating-square pillar, three second flat dielectric pillars and a background dielectric is a low-refractive-index dielectric; and an normalized operating frequency of the TEOS is 0.4057 to 0.406.

This application claims priority to Chinese Application No. 201410759245.2 filed on Dec. 10, 2014 and is a continuation of International Application No. PCT/CN2015/097055 filed on Dec. 10, 2015 and published in Chinese as International Publication No. WO/2016/091195 on Jun. 16, 2016, the entire contents of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates generally to a TE optical switch (TEOS) with high extinction ratio (EXR), and specifically to a broadband TEOS with a high EXR based on slab photonic crystals (PhCs) with absolute bandgaps.

BACKGROUND OF THE INVENTION

In recent years, with the advent of information age, the speed and amount of information required for communication technology increase dramatically. Optical communication technologies add wings to the information age, but the information processing of nodes and routes still need electronic circuits at present, which restricts the development of communication technologies in terms of speed, capacity and power consumption. Adopting photonic integrated circuits to replace or partially replace electronic integrated circuits for communication routes certainly will become the future direction of development. A PhC is a structure material in which dielectric materials are arranged periodically in space, and is usually an artificial crystal including of two or more materials having different dielectric constants. The electromagnetic modes in an absolute photonic bandgap (PBG) cannot exist completely, so as an electronic energy band is overlapped with the absolute bandgap of PhCs, spontaneous radiation is suppressed. The PhC having the absolute bandgap can control spontaneous radiation, thereby changing the interaction between the fields and materials, and further improving the performance of optical devices.

Tunable PBGS can be applied to information communication, display and storage. For modulating bandgaps at high speeds by using external driving sources, many solutions have been proposed, e.g., controlling magnetic permeability by using a ferromagnetic material, and changing dielectric constant by using a ferroelectric material.

Most of the existing optical switches are realized by using a nonlinear effect, which requires the use of high-power light for control, thus it will inevitably consume a large amount of energy. In the presence of large-scale integrated system and a large number of communication users, the consumption of energy will become enormous. At the same time, the degree of polarization will affect signal-to-noise ratio and transmission speed.

SUMMARY OF THE INVENTION

The present invention is aimed at overcoming the defects of the prior art and providing a TEOS with a high EXR based on slab PhCs.

The technical solution proposal adopted by the invention to solve the technical problem is as follows:

A TEOS with high EXR based on slab PhCs in the present invention includes an upper slab

PhC and a lower slab PhC connected as a whole; the upper slab PhC is a first square-lattice slab PhC, the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating-square pillar, three first flat dielectric pillars and a background dielectric, the first flat dielectric pillars are arranged horizontally, the first flat dielectric pillars enable an overall upper slab PhC to form as a whole, and the first flat dielectric pillars include a high-refractive-index dielectric pipe and a low-refractive-index dielectric, or 1 to 3 high-refractive-index flat thin films, or a low-refractive-index dielectric; the lower slab PhC is a second square-lattice slab PhC with a complete bandgap, the unit cell of the second square-lattice slab PhC includes a high-refractive-index rotating-square pillar, three second flat dielectric pillars and a background dielectric, the second flat dielectric pillars are arranged horizontally, the second flat dielectric pillars enable an overall lower slab PhC to form as a whole, and the second flat dielectric pillars are high-refractive-index dielectric pillars; said background dielectric is a low-refractive-index dielectric; and an normalized operating frequency of said TEOS is 0.4057 to 0.406, 0.4267 to 0.4329, or 0.44 to 0.479.

The thickness of the pipe wall in the first dielectric pillar in the unit cell of the first square-lattice slab PhC is 0-0.009a, where a is the lattice constant of the PhC; and the width of the low-refractive-index dielectric in the pipe is the difference between the width of the first flat dielectric pillar and the thickness of the pipe wall.

The one of first flat dielectric pillars in the unit cell of the first square-lattice slab PhC is located at the horizontal middle of the center of the rotating-square pillar, the remaining two first flat dielectric pillars are parallel to the first flat dielectric pillar in the horizontal middle respectively, and the distance of the remaining two first flat dielectric pillars at the left and right is 0.25a.

The side lengths of the high-refractive-index rotating-square pillars of the first and second square-lattice slab PhCs are respectively 0.545a to 0.554a, and their rotating angles are 0 to 90°; and the widths of the first and second flat dielectric pillars in the unit cell of the first and second square-lattice slab PhCs are respectively 0.029a to 0.034a.

The high-refractive-index dielectric is silicon, gallium arsenide, titanium dioxide or a different dielectric having a refractive index of more than 2; and the low-refractive-index dielectric is vacuum, air, cryolite, silica, organic foam, olive oil or a different dielectric having a refractive index of less than 1.5.

The TEOS has one state that the first square-lattice slab PhC is located in an optical channel (OCH) and the second square-lattice slab PhC is located outside the OCH, and the other state that the second square-lattice slab PhC is located in the OCH and the first square-lattice slab PhC is located outside the OCH.

In the case that the normalized operating frequency range of the TEOS is 0.4057 to 0.406, the EXR is −14 dB to −15 dB; the state, wherein the first square-lattice slab PhC is located in the OCH and the second square-lattice slab PhC is located outside the OCH, is an optically connected state; and the state, wherein the second slab square-lattice PhC is located in the OCH and the first square-lattice slab PhC is located outside the OCH, is an optically disconnected state.

In the case that the normalized operating frequency range of the TEOS is 0.4267 to 0.4329, the EXR is −32 dB to −35 dB; the state, wherein the second square-lattice slab PhC is located in the OCH and the first square-lattice slab PhC is located outside the OCH, is an optically connected state; and the state, wherein the first square-lattice slab PhC is located in the OCH and the second square-lattice slab PhC is located outside the OCH, is an optically disconnected state.

In the case that the normalized operating frequency range of the TEOS is 0.44 to 0.479, the EXR is −20 dB to −40 dB; the state, wherein the second square-lattice slab PhC is located in the OCH and the first square-lattice slab PhC is located outside the OCH, is an optically connected state; and the state, wherein the first square-lattice slab PhC is located in the OCH and the second square-lattice slab PhC is located outside the OCH, is an optically disconnected state.

The positions of the first and the second square-lattice slab PhC in the OCH are adjusted by external forces, including mechanical, electrical and magnetic forces.

In the case that the normalized operating frequency range of the TEOS is 0.4057 to 0.406, the EXR is −14 dB to −15 dB; the state, wherein the first square-lattice slab PhC is located in the OCH and the second square-lattice slab PhC is located outside the OCH, is an optically connected state; and the state, wherein the second square-lattice slab PhC is located in the OCH and the first square-lattice slab PhC is located outside the OCH, is an optically disconnected state.

In the case that the normalized operating frequency range of the TEOS is 0.4267 to 0.4329, the EXR is −32 dB to −35 dB; the state, wherein the second square-lattice slab PhC is located in the OCH and the first square-lattice slab PhC is located outside the OCH, is an optically connected state; and the state, wherein the first square-lattice slab PhC is located in the OCH and the second square-lattice slab PhC is located outside the OCH, is an optically disconnected state.

In the case that the normalized operating frequency range of the TEOS is 0.44 to 0.479, the EXR is −20 dB to −40 dB; the state, wherein the second square-lattice slab PhC is located in the OCH and the first square-lattice slab PhC is located outside the OCH, is an optically connected state; and the state, wherein the first square-lattice slab PhC is located in the OCH and the second square-lattice slab PhC is located outside the OCH, is an optically disconnected state.

Compared with the prior art, the present invention has the following positive effects.

1. The optical switch is an indispensable component in an integrated optical circuit and is very important for high-speed operation of a network, and large bandwidth, low energy loss, high polarization degree and high EXR are important parameters for evaluating switches.

2. The functions of the optical switch are realized by adjusting the positions of the first square-lattice slab PhC (the upper slab PhC) and the second square-lattice slab PhC (the lower slab PhC) in the OCH.

3. The structure of the present invention enables a TEOS with a high EXR.

4. The TEOS with a high EXR based on slab PhCs facilitates optical integration.

These and other objects and advantages of the present invention will become readily apparent to those skilled in the art upon reading the following detailed description and claims and by referring to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(a) is a structural schematic diagram of a unit cell of an upper slab PhC of a TEOS of the present invention.

FIG. 1(b) is a structural schematic diagram of a unit cell of a lower slab PhC of the TEOS of the present invention.

FIG. 2(a) is a structural schematic diagram of a first implementation of the TEOS with a high EXR based on slab PhCs of the present invention.

FIG. 2(b) is a structural schematic diagram of a second implementation of the TEOS with a high EXR based on slab PhCs of the present invention.

FIG. 2(c) is a structural schematic diagram of a third implementation of the TEOS with a high EXR based on slab PhCs of the present invention.

FIG. 3 is a photonic band map of the second square-lattice slab PhC shown in embodiment 1.

FIG. 4 is a photonic band map of the first square-lattice slab PhC shown in embodiment 1.

FIG. 5 is a photonic band map of the second square-lattice slab PhC shown in embodiment 2.

FIG. 6 is a photonic band map of the first square-lattice slab PhC shown in embodiment 2.

FIG. 7 is an optical field (electric field) distribution diagram of the TEOS for the normalized operating frequency of 0.4057 as shown in embodiment 3, wherein the wave is incident from top, the left-hand-side plot shows the OFF state that the wave cannot go through, and the right-hand-side plot shows the ON state that the wave can go through.

FIG. 8 is an optical field (electric field) distribution diagram of the TEOS for the normalized operating frequency of 0.4058 as shown in embodiment 4, wherein the wave is incident from top, the left-hand-side plot shows the OFF state that the wave cannot go through, and the right-hand-side plot shows the ON state that the wave can go through.

FIG. 9 is an optical field (electric field) distribution diagram of the TEOS for the normalized operating frequency of 0.406 as shown in embodiment 5, wherein the wave is incident from top, the left-hand-side plot shows the OFF state that the wave cannot go through, and the right-hand-side plot shows the ON state that the wave can go through.

FIG. 10 is an optical field (electric field) distribution diagram of the TEOS for the normalized operating frequency of 0.4267 as shown in embodiment 6, wherein the wave is incident from top, the left-hand-side plot shows the OFF state that the wave cannot go through, and the right-hand-side plot shows the ON state that the wave can go through.

FIG. 11 is an optical field (electric field) distribution diagram of the TEOS for the normalized operating frequency of 0.4315 as shown in embodiment 7, wherein the wave is incident from top, the left-hand-side plot shows the ON state that the wave cannot go through, and the right-hand-side plot shows the OFF state that the wave can go through.

FIG. 12 is an optical field (electric field) distribution diagram of the TEOS for the normalized operating frequency of 0.4329 as shown in embodiment 8, wherein the wave is incident from top, the left-hand-side plot shows the OFF state that the wave cannot go through, and the right-hand-side plot shows the ON state that the wave can go through.

FIG. 13 is an optical field (electric field) distribution diagram of the TEOS for the normalized operating frequency of 0.44 as shown in embodiment 9, wherein the wave is incident from top, the left-hand-side plot shows the OFF state that the wave cannot go through, and the right-hand-side plot shows the ON state that the wave can go through.

FIG. 14 is an optical field (electric field) distribution diagram of the TEOS for the normalized operating frequency of 0.4435 as shown in embodiment 10, wherein the wave is incident from top, the left-hand-side plot shows the ON state that the wave cannot go through, and the right-hand-side plot shows the OFF state that the wave can go through.

FIG. 15 is an optical field (electric field) distribution diagram of the TEOS for the normalized operating frequency of 0.452 as shown in embodiment 11, wherein the wave is incident from top, the left-hand-side plot shows the OFF state that the wave cannot go through, and the right-hand-side plot shows the ON state that the wave can go through.

FIG. 16 is an optical field (electric field) distribution diagram of the TEOS for the normalized operating frequency of 0.456 as shown in embodiment 12, wherein the wave is incident from top, the left-hand-side plot shows the ON state that the wave cannot go through, and the right-hand-side plot shows the OFF state that the wave can go through.

FIG. 17 is an optical field (electric field) distribution diagram of the TEOS for the normalized operating frequency of 0.479 as shown in embodiment 13, wherein the wave is incident from top, the left-hand-side plot shows the ON state that the wave cannot go through, and the right-hand-side plot shows the OFF state that the wave can go through.

The present invention is more specifically described in the following paragraphs by reference to the drawings attached only by way of example.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The terms a or an, as used herein, are defined as one or more than one, The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more.

The present invention will be further described in detail below in combination with the accompanying drawings and specific embodiments.

ATEOS with a high EXR based on slab PhCs in the present invention, as shown in FIG. 1(a), includes an upper slab PhC and a lower slab PhC connected as a whole; the upper slab PhC is a first square-lattice slab PhC, the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating-square pillar, the three first flat dielectric pillars and a background dielectric, the first flat dielectric pillars are arranged horizontally, the first flat dielectric pillars enable the overall upper slab PhC to form as a whole, and the first flat dielectric pillars are included of a high-refractive-index dielectric pipe and a low-refractive-index dielectric in the pipe, or 1 to 3 of a high-refractive-index flat films, or a low-refractive-index dielectric; as shown in FIG. 1(b); the lower slab PhC is a second square-lattice slab PhC with a complete bandgap, the unit cell of the second square-lattice slab PhC is included of a high-refractive-index rotating-square pillar, 3 single second flat dielectric pillars and a background dielectric, the second flat dielectric pillars are arranged horizontally, the second flat dielectric pillars enable the overall lower slab PhC to form as a whole, the second flat dielectric pillars are high-refractive-index dielectric pillars, and the high-refractive-index dielectric is silicon, gallium arsenide, titanium dioxide or a different dielectric having a refractive index of more than 2; the background dielectric is a low-refractive-index dielectric, and the low-refractive-index dielectric is vacuum, air, cryolite, silica, organic foam, olive oil or a different dielectric having a refractive index of less than 1.5.

The normalized operating frequency (a/λ) of the TEOS with a high EXR is 0.4057 to 0.406, 0.4267 to0.4392 or 0.44 to 0.479, and this frequency range is either the TE transmission band of the first slab PhC and the bandgap of the second square-lattice slab PhC, or the second square-lattice slab PhC and the TE transmission band and TE bandgap of the first square-lattice slab PhC, wherein a is a lattice constant of the first and second square-lattice slab PhCs, and λ is the wavelength of incident wave.

For the normalized operating frequency (a/λ) of the TEOS with a high EXR being 0.4057 to 0.406, the EXR is −14 dB to −15 dB, the state, wherein the first square-lattice slab PhC is located in the OCH and the second square-lattice slab PhC is located outside the OCH, is a first switch state of the TEOS, i.e., optically connected state; and the state, wherein the second slab PhC is located in the OCH and the first square-lattice slab PhC is located outside the OCH, is a second switch state of the TEOS, i.e., optically disconnected state; and the state, wherein the first slab lattice PhC is located in the OCH and the second square-lattice slab PhC is located outside the OCH, is an optically connected state; the state, wherein the second square-lattice slab PhC is located in the OCH and the first square-lattice slab PhC is located outside the OCH, is an optically disconnected state;

For the normalized operating frequency range (a/λ) of the TEOS being 0.4267 to 0.4329, the EXR is −32 dB to −35 dB; the state, wherein the second square-lattice slab PhC is located in the OCH and the first square-lattice slab PhC is located outside the OCH, is an optically connected state; and the state, wherein the first square-lattice slab PhC is located in the OCH and the second square-lattice slab PhC is located outside the OCH, is an optically disconnected state;

For the normalized operating frequency (a/λ) of the high EXR TEOS being 0.44 to 0.479, the EXR is −20 dB to −40 dB; the state, wherein the second square-lattice slab PhC s is located in the OCH and the first square-lattice slab PhC is located outside the OCH, is an optically connected state; and the state, wherein the first square-lattice slab PhC is located in the OCH and the second square-lattice slab PhC is located outside the OCH, is an optically disconnected state.

The EXR of the TEOS is a ratio of the output optical powers of the switch in the two states.

The First Implementation of the TEOS with a High EXR Based on Slab PhC of the Present Invention.

The TEOS with a high EXR includes an upper slab PhC and a lower slab PhC connected as a whole; as shown in FIG. 2 (a), wherein the rotating-square pillars in the PhCs are omitted, and the dashed box shows the position of a rotating-square pillar array; the upper slab PhC is a first square-lattice slab PhC, the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating-square pillar, the three first flat dielectric pillars and a background dielectric, the first flat dielectric pillars are arranged horizontally, one of first flat dielectric pillars in the unit cell of a first square-lattice slab PhC is located at the horizontal middle of the center of the rotating-square pillar, the remaining two first flat dielectric pillars are parallel to the first flat dielectric pillar in the horizontal middle respectively, and the distance of the remaining two at the left and right is 0.25a, the first flat dielectric pillars enable the overall upper slab PhC to form as a whole, the first flat dielectric pillars are composed of a high-refractive-index pipe and a low-refractive-index dielectric in the pipe, the thickness of the pipe wall in the first flat dielectric pillar in the unit cell of the first square-lattice slab PhC is 0 to 0.009a; and the width of the low-refractive-index dielectric in the pipe is the difference between the width of the first flat dielectric pillar and the thickness of the pipe wall. The lower slab PhC is a second square-lattice slab PhC with a complete bandgap, the unit cell of the second square-lattice slab PhC is composed of a high-refractive-index rotating-square pillar, the three second flat dielectric pillars and a background dielectric, the second flat dielectric pillars are arranged horizontally, the second flat dielectric pillars enable the overall lower slab PhC to form as a whole, one of second flat dielectric pillars of a second square-lattice slab PhC is located at the horizontal middle of the center of the rotating-square pillar, the remaining two second flat dielectric pillars are parallel to the second flat dielectric pillar at the horizontal middle respectively, and the distance of the remaining two at the left and right is 0.25a. The side lengths of the high-refractive-index rotating-square pillars of the first and second square-lattice slab PhCs are respectively 0.545a to 0.564a, their rotating angles are 0° to 90°, and the widths of the first and second flat dielectric pillars in the unit cells of the first and second square-lattice slab PhCs are respectively 0.029a to 0.034a; the second flat dielectric pillars are high-refractive-index dielectric pillars, the high-refractive-index medium is silicon, gallium arsenide, titanium dioxide or a different dielectric having a refractive index of more than 2, and the high-refractive-index dielectric adopts a silicon material; the background dielectric is a low-refractive-index dielectric, and the low-refractive-index dielectric is vacuum, air, cryolite, silica, organic foam, olive oil or a different dielectric having a refractive index of less than 1.5. The normalized operating frequency (a/λ) range of the EXR with a high EXR is 0.4057 to 0.406,and this frequency range is either the TE transmission band of the first square-lattice slab PhC and the TE bandgap of the second square-lattice slab PhC, or the second square-lattice slab PhC and the TE transmission band and TE bandgap of the first square-lattice slab PhC, wherein a is a lattice constant of the first and second square-lattice slab PhCs, and A is the wavelength of incident wave.

The Second Implementation of the TEOS with a High EXR Based on Slab PhCs of the Present Invention.

The TEOS comprises an upper slab PhC and a lower slab PhC connected as a whole; as shown in FIG. 2(b), rotating-square pillars in the PhCs are omitted in the figure, and the dashed box shows the position of a rotating-square pillar array; the upper slab PhC is a first square-lattice slab PhC, the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating-square pillar, the three first flat dielectric pillars and a background dielectric, the first flat dielectric pillars are arranged horizontally, one of first flat dielectric pillars in the unit cell of a first square-lattice slab PhC is located at the horizontal middle of the center of the rotating-square pillar, the remaining two first flat dielectric pillars are parallel to the first flat dielectric pillar in the horizontal middle respectively, and the distance of the remaining two at the left and right is 0.25a; the first flat dielectric pillars enable the overall upper slab PhC to form as a whole, and the first flat dielectric pillars include three high-refractive-index flat films; the lower slab PhC is a second square-lattice slab PhC with a complete bandgap, the unit cell of the second square-lattice slab PhC is included of a high-refractive-index rotating-square pillar, the three second flat dielectric pillars and a background dielectric, the second flat dielectric pillars are arranged horizontally, the second flat dielectric pillars enable the overall lower slab PhC to form as a whole, one of second flat dielectric pillars of a second square-lattice slab PhC is located at the horizontal middle of the center of the rotating-square pillar, the remaining two second flat dielectric pillars are parallel to the second flat dielectric pillar in the horizontal middle respectively, and the distance of the remaining two second flat dielectric pillars at the left and right is 0.25a, the side lengths of the high-refractive-index rotating-square pillars of the first and second square-lattice slab PhCs are respectively 0.545a to 0.564a, their rotating angles are 0° to 90°, and the widths of the first and second flat dielectric pillars in the unit cell of the first and second square-lattice slab PhCs are respectively 0.029a to 0.034a. The second flat dielectric pillar is a high-refractive-index dielectric pillar, the high-refractive-index dielectric is silicon, gallium arsenide, titanium dioxide or a different dielectric having a refractive index of more than 2, and the high-refractive-index dielectric adopts a silicon material; the background dielectric is a low-refractive-index dielectric, and the low-refractive-index dielectric is vacuum, air, cryolite, silica, organic foam, olive oil or a different dielectric having a refractive index of less than 1.5. The normalized operating frequency (a/λ) range of the TEOS with a high EXR is 0.4267 to 0.4329, and this frequency range is either the TE transmission band of the first square-lattice slab PhC and the TE bandgap of the second square-lattice slab PhC, or the second square-lattice slab PhC and the TE transmission band and TE bandgap of the first square-lattice slab PhC, wherein a is a lattice constant of the first and second square-lattice slab PhCs, and A is the wavelength of incident wave.

The Third Implementation of the TEOS with a High EXR Based on Slab PhCs of the Present Invention.

The TEOS comprises an upper slab PhC and a lower slab PhC connected as a whole; as shown in FIG. 2(c), rotating-square pillars in the PhCs are omitted in the figure, and the dashed box shows the position of a rotating-square pillar array. The upper slab PhC is a first square-lattice slab PhC, the unit cell of the first square-lattice slab PhC includes a high-refractive-index rotating-square pillar, a single first flat dielectric pillar and a background dielectric, the first flat dielectric pillar is composed of a low-refractive-index dielectric, the background dielectric is a low-refractive-index dielectric, the three slots are formed in the high-refractive-index rotating-square pillar and are filled with the low-refractive-index dielectric, and the low-refractive-index dielectric is vacuum, air, cryolite, silica, organic foam, olive oil or a different dielectric having a refractive index of less than 1.5, e.g., the slot is filled with air. The lower slab PhC is a second square-lattice slab PhC with a complete bandgap, the unit cell of the second square-lattice slab PhC includes a high-refractive-index rotating-square pillar, the three second flat dielectric pillars and a background dielectric, the second flat dielectric pillars are arranged horizontally, the second flat dielectric pillars enable the overall lower slab PhC to form as a whole; one of second flat dielectric pillars in the unit cell of a second square-lattice slab PhC is located at the horizontal middle of the center of the rotating-square pillar, the remaining two second flat dielectric pillars are parallel to the second flat dielectric pillar in the horizontal middle respectively, and the distance of the remaining two second flat dielectric pillars at the left and right is 0.25a, the side lengths of the high-refractive-index rotating-square pillars of the second square-lattice slab PhCs are respectively 0.545a to 0.564a, and their rotating angles are 0° to 90°; the widths of the second flat dielectric pillars of the second square-lattice slab PhCs in the call are respectively 0.029a to 0.034a; the second flat dielectric pillars are high-refractive-index dielectric pillars, the high-refractive-index dielectric is silicon, gallium arsenide, titanium dioxide or a different dielectric having a refractive index of more than 2, and the high-refractive-index dielectric adopts a silicon material; the background dielectric is a low-refractive-index dielectric; The normalized operating frequency (a/λ) range of the TEOS with a high EXR is 0.44a to 0.479a, and this frequency range is either the TE transmission band of the first square-lattice slab PhC and the TE bandgap of the second square-lattice slab PhC, or the second square-lattice slab PhC and the TE transmission band and TE bandgap of the first square-lattice slab PhC, wherein a is a lattice constant of the first and second square-lattice slab PhCs, and A is the wavelength of incident wave.

The a fore three implementations all take a paper surface as the reference plane, and the upper and lower slab PhCs are connected as a whole by a frame and move vertically under the action of external forces to realize the functions of the TEOS, as shown in FIG. 2. Rotating-square pillars in the PhCs are omitted in the figure, and the dashed box shows the position of a rotating-square pillar array. Because the frame itself is not on the light input and output planes, i.e., the light input and output planes are parallel to the reference plane, the propagation of light is not influenced. The vertical movement of the upper and lower slab PhCs serving as a whole can be realized by micromechanical, electrical or magnetic forces. For example, a magnet may be embedded into the frame, a pressure linkage device is connected with the frame, the pressure can thus drive the black frame to move up and down, and the left and right sides of the frame are located in a groove guide rail to guarantee that the black frame moves vertically, linearly and reciprocally.

Embodiment 1

In this embodiment, different photonic band maps in a horizontal direction are obtained through the first and second square-lattice slab PhCs, FIG. 3 is a photonic band map of the second square-lattice slab PhC, the TE bandgap normalization frequency (a/λ) is 0.400 to 0.4325; FIG. 4 is a photonic band map of the first square-lattice slab PhC, the TE bandgap normalization frequency (a/λ) is 0.4303 to 0.5216, and it can be known by comparison that for the normalized operating frequency (a/λ) range of 0.400 to 0.4303, this structure enables a TEOS with a high EXR.

Embodiment 2

In this embodiment, different photonic band maps in a vertical direction are obtained through the first and second square-lattice slab PhCs, FIG. 5 is a photonic band map of the second square-lattice slab PhC, the TE bandgap normalization frequency (a/λ) is 0.400 to 0.4325; FIG. 6 is a photonic band of the first square-lattice slab PhC, the TE bandgap normalization frequency (a/λ) is 0.4303 to 0.5216, and it can be known by comparison that for the normalized operating frequency (a/λ) range being 0.400 to 0.4303, this structure enables a TEOS with a high EXR.

Embodiment 3

In this embodiment, the normalized operating frequency (a/λ) is 0.4057. By adopting the first implementation and verifying with three-dimensional (3D) structure parameters for nine layers of high-refractive-index rotating dielectric pillars and thirty-seven layers of high-refractive-index dielectric veins, the result is illustrated in FIG. 7. It can be known from FIG. 7 that: the TEOS has good extinction effect.

Embodiment 4

In this embodiment, the normalized operating frequency (a/λ) is 0.4058. By adopting the first implementation and verifying with 3D structure parameters for nine layers of high-refractive-index rotating dielectric pillars and thirty-seven layers of high-refractive-index dielectric veins, the result is illustrated in FIG. 8. It can be known from FIG. 8 that: the TEOS has good extinction effect.

Embodiment 5

In this embodiment, the normalized operating frequency (a/λ) is 0.406. By adopting the first implementation and verifying with 3D structure parameters for nine layers of high-refractive-index rotating dielectric pillars and thirty-seven layers of high-refractive-index dielectric veins, the result is illustrated in FIG. 9. It can be known from FIG. 9 that: the TEOS has good extinction effect.

Embodiment 6

In this embodiment, the normalized operating frequency (a/λ) is 0.4267. By adopting the second implementation and verifying with 3D structure parameters for nine layers of high-refractive-index rotating dielectric pillars and thirty-seven layers of high-refractive-index dielectric veins, the result is illustrated in FIG. 10. It can be known from FIG. 10 that: the TEOS has good extinction effect.

Embodiment 7

In this embodiment, the normalized operating frequency (a/λ) is 0.4315. By adopting the second implementation and verifying with 3D structure parameters for nine layers of high-refractive-index rotating dielectric pillars and thirty-seven layers of high-refractive-index dielectric veins, the result is illustrated in FIG. 11. It can be known from FIG. 11 that: the TEOS has good extinction effect.

Embodiment 8

In this embodiment, the normalized operating frequency (a/λ) is 0.4329. By adopting the second implementation and verifying with 3D structure parameters for nine layers of high-refractive-index rotating dielectric pillars and thirty-seven layers of high-refractive-index dielectric veins, the result is illustrated in FIG. 12. It can be known from FIG. 12 that: the TEOS has good extinction effect.

Embodiment 9

In this embodiment, the normalized operating frequency (a/λ) is 0.44. By adopting the three implementations and verifying with 3D structure parameters for nine layers of high-refractive-index rotating dielectric pillars and thirty-seven layers of high-refractive-index dielectric veins, the result is illustrated in FIG. 13. It can be known from FIG. 13 that: the TEOS has good extinction effect.

Embodiment 10

In this embodiment, the normalized operating frequency (a/λ) is 0.4435. By adopting the three implementations and verifying with 3D structure parameters for nine layers of high-refractive-index rotating dielectric pillars and thirty-seven layers of high-refractive-index dielectric veins, the result is illustrated in FIG. 14. It can be known from FIG. 14 that: the TEOS has good extinction effect.

Embodiment 11

In this embodiment, the normalized operating frequency (a/λ) is 0.452. By adopting the three implementations and verifying with 3D structure parameters for nine layers of high-refractive-index rotating dielectric pillars and thirty-seven layers of high-refractive-index dielectric veins, the result is illustrated in FIG. 15. It can be known from FIG. 15 that: the TEOS has good extinction effect.

Embodiment 12

In this embodiment, the normalized operating frequency (a/λ) is 0.456. By adopting the three implementations and verifying with 3D structure parameters for nine layers of high-refractive-index rotating dielectric pillars and thirty-seven layers of high-refractive-index dielectric veins, the result is illustrated in FIG. 16. It can be known from FIG. 16 that: the TEOS has good extinction effect.

Embodiment 13

In this embodiment, the normalized operating frequency (a/λ) is 0.479. By adopting the three implementations and verifying with 3D structure parameters for nine layers of high-refractive-index rotating dielectric pillars and thirty-seven layers of high-refractive-index dielectric veins, the result is illustrated in FIG. 17. It can be known from FIG. 17 that: the TEOS has good extinction effect.

While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims. 

What is claimed is:
 1. A TEOS with a high EXR based on slab PhCs, wherein said TEOS with a high EXR based on slab PhCs comprising: an upper slab PhC and a lower slab PhC connected as a whole; said upper slab PhC is a first square-lattice slab PhC, the unit cell of said first square-lattice slab PhC includes a high-refractive-index rotating-square pillar, three first flat dielectric pillars and a background dielectric, said first flat dielectric pillars are arranged horizontally, said first flat dielectric pillars enable an overall upper slab PhC to form as a whole, and said first flat dielectric pillars include a high-refractive-index dielectric pipe and a low-refractive-index dielectric, or 1 to 3 high-refractive-index flat films, or a low-refractive-index dielectric; said lower slab PhC is a second square-lattice slab PhC with a complete bandgap, the unit cell of said second square-lattice slab PhC includes a high-refractive-index rotating-square pillar, three second flat dielectric pillars and a background dielectric, said second flat dielectric pillars are arranged horizontally, said second flat dielectric pillars enable an overall lower slab PhC to form as a whole, and said second flat dielectric pillars are high-refractive-index dielectric pillars; said background dielectric is a low-refractive-index dielectric; and an normalized operating frequency of said TEOS is 0.4057 to 0.406, 0.4267 to 0.4329, or 0.44 to 0.479.
 2. The TEOS with a high EXR based on slab PhCs according to claim 1, wherein the thickness of the pipe wall in said first flat dielectric pillar in the unit cell of said first square-lattice slab PhC is 0-0.009a, where a is the lattice constant of the PhC; and the width of the low-refractive-index dielectric in the pipe is the difference between the width of said first flat dielectric pillar and the thickness of the pipe.
 3. The TEOS with a high EXR based on slab PhCs according to claim 1, wherein one of first flat dielectric pillars in the unit cell of said first square-lattice slab PhC is located at the horizontal middle of a center of said rotating-square pillar, the remaining two first flat dielectric pillars are parallel to said first flat dielectric pillar in the horizontal middle respectively, and a distance between the remaining two first flat dielectric pillars at a left and right is 0.25a.
 4. The TEOS with a high EXR based on slab PhCs according to claim 1, wherein the side lengths of said high-refractive-index rotating-square pillars of said first and second square-lattice slab PhCs are respectively 0.545a to 0.554a, and their rotating angles are 0 to 90°; and the widths of the first and second flat dielectric pillars in the unit cell of said first and second square-lattice slab PhCs are respectively 0.029a to 0.034a.
 5. The TEOS with a high EXR based on slab PhCs according to claim 1, wherein said high-refractive-index dielectric is silicon, gallium arsenide, titanium dioxide or a different dielectric having a refractive index of more than 2; and the low-refractive-index dielectric is vacuum, air, cryolite, silica, organic foam, olive oil or a different dielectric having a refractive index of less than 1.5.
 6. The TEOS with a high EXR based on slab PhCs according to claim 1, wherein said TEOS has one state that said first square-lattice slab PhC is located in an OCH and said second square-lattice slab PhC is located outside the OCH, and another state that said second square-lattice slab PhC is located in the OCH and said first square-lattice slab PhC is located outside the OCH.
 7. The TEOS with a high EXR based on slab PhCs according to claim 1, wherein the normalized operating frequency range of said TEOS is 0.4057 to 0.406, the EXR is −14 dB to −15 dB; the state, wherein said first square-lattice slab PhC is located in the OCH and said second square-lattice slab PhC is located outside the OCH, is the optically connected state; and the state, wherein said second square-lattice slab PhC is located in the OCH and said first square-lattice slab PhC is located outside the OCH, is the optically disconnected state.
 8. The TEOS with a high EXR based on slab PhCs according to claim 1, wherein said normalized operating frequency range of the TEOS is 0.4267 to 0.4329, the EXR is −32 dB to −35 dB; the state, wherein said second square-lattice slab PhC is located in the OCH and said first square-lattice slab PhC is located outside the OCH, is the optically connected state; and the state, wherein said first square-lattice slab PhC is located in the OCH and said second square-lattice slab PhC is located outside the OCH, is an optically disconnected state.
 9. The TEOS with a high EXR based on slab PhCs according to claim 1, wherein said normalized operating frequency range of the TEOS is 0.44 to 0.479, the EXR is −20 dB to −40 dB; the state, wherein aid second square-lattice slab PhC is located in the OCH and said first square-lattice slab PhC is located outside the OCH, is the optically connected state; and the state, wherein said first square-lattice slab PhC is located in the OCH and said second square-lattice slab PhC is located outside the OCH, is an optically disconnected state.
 10. The TEOS with a high EXR based on slab PhCs according to claim 1, wherein positions of said first and second square-lattice slab PhCs in the OCHs are adjusted by external forces, including mechanical, electrical and magnetic forces.
 11. The TEOS with a high EXR based on slab PhCs according to claim 7, wherein said normalized operating frequency range of the TEOS is 0.4057 to 0.406, the EXR is −14 dB to −15 dB; the state, wherein said first square-lattice slab PhC is located in the OCH and the second square-lattice slab PhC is located outside the OCH, is the optically connected state; and the state, wherein said second square-lattice slab PhC is located in the OCH and said first square-lattice slab PhC is located outside the OCH, is an optically disconnected state.
 12. The TEOS with a high EXR based on slab PhCs according to claim 7, wherein said normalized operating frequency range of the TEOS is 0.4267 to 0.4329, the EXR is −32 dB to −35 dB; the state, wherein the second square-lattice slab PhC is located in the OCH and the first square-lattice slab PhC is located outside the OCH, is an optically connected state; and the state, wherein the first square-lattice slab PhC is located in the OCH and the second square-lattice slab PhC is located outside the OCH, is an optically disconnected state.
 13. The TEOS with a high EXR based on slab PhCs according to claim 7, wherein said normalized operating frequency range of the TEOS is 0.44 to 0.479, the EXR is −20 dB to −40 dB; the state, wherein said second square-lattice slab PhC is located in the OCH and the first square-lattice slab PhC is located outside the OCH, is an optically connected state; and the state, wherein said first square-lattice slab PhC is located in the OCH and said second square-lattice slab PhC is located outside the OCH, is an optically disconnected state. 